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Register a new userExplaining muon $g-2$ anomaly in a non-universal $U(1)_{X}$ extended SUSY theory
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A non-universal $U(1)_{X}$ extension to the Standard Model composed of two scalar doublets and two scalar singlets together with three additional quark singlets and two lepton singlets and three generations of right-handed and Majorana neutrinos is made to explain lepton mass hierarchy, neutrino masses via inverse seesaw mechanism and muon anomalous magnetic moment in an anomaly free framework. In the present model, exotic and Standard Model particles acquire mass thanks to vacuum expectation values at different scales, yet the electron and the lightest neutrino are tree level massless but massive at one-loop level. By considering a numerical exploration and under the constraint of the Higgs mass, neutrino mass differences and PMNS matrix, it is found that only contributions due to exotic neutrinos interacting with charged scalars are relevant to muon $g-2$, though they are negative. Thus, the SUSY extension is considered and it is found that muon $g-2$ can be explained by allowing $U(1)_{X}$ vacuum expectation values to lie in the TeV scale thanks to SUSY soft-breaking interactions for at least $sim 10^{5}$ GeV masses. Thus, the contribution due to exotic neutrinos interacting with $W$ gauge bosons is positive and no longer negligible which added to all other contributions might explain the anomaly.
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We propose a SUSY scenario to explain the current electron and muon $g-2$ discrepancies without introducing lepton flavor mixings. Threshold corrections to the Yukawa couplings can enhance the electron $g-2$ and flip the sign of the SUSY contributions. The mechanism predicts a flavor-dependent slepton mass spectrum. We show that it is compatible with the Higgs mediation scenario.
The long-standing muon $g-2$ anomaly has been confirmed recently at the Fermilab. The combined discrepancy from Fermilab and Brookhaven results shows a difference from the theory at a significance of 4.2 $sigma$. In addition, the LHC has updated the lower mass bound of a pure wino. In this letter, we study to what extent the $g-2$ can be explained in anomaly mediation scenarios, where the pure wino is the dominant dark matter component. To this end, we derive some model-independent constraints on the particle spectra and $g-2$. We find that the $g-2$ explanation at the 1$sigma$ level is driven into a corner if the higgsino threshold correction is suppressed. On the contrary, if the threshold correction is sizable, the $g-2$ can be explained. In the whole viable parameter region, the gluino mass is at most $2-4,$TeV, the bino mass is at most $2,$TeV, and the wino dark matter mass is at most $1-2,$TeV. If the muon $g-2$ anomaly is explained in the anomaly mediation scenarios, colliders and indirect search for the dark matter may find further pieces of evidence in the near future. Possible UV models for the large threshold corrections are discussed.
We consider right-handed neutrino dark matter $N_1$ in local $U(1)_{L_mu-L_tau}$-extended Ma model. With the light $U(1)_{mu-tau}$ gauge boson ($m_{Z} sim {cal O}(100)$ MeV) and small $U(1)_{mu-tau}$ gauge coupling ($g_{Z}sim 10^{-4}-10^{-3}$) which can accommodate the muon $(g-2)$ anomaly and is still allowed by other experimental constraints, we show that we can get correct relic density of dark matter for wide range of dark matter mass ($M_1 sim 10-100$ GeV), although the gauge coupling constant $g_{Z}$ is small. This is due to the fact that the annihilation cross section of dark matter pair is enhanced by $M_1^4/m_{Z}^4$ in the processes $N_1 N_1 to Z Z$ or $N_1 N_1 to Z H_2$. We also consider the constraints from direct detection, collider searches.
We propose a U(1)^prime mediated supersymmetry (SUSY) breaking, in which U(1)^prime is identified with U(1)_{B_1+B_2-2L_1}. The U(1)_{B_1+B_2-2L_1} gauge symmetry, which is anomaly-free with the field contents of the minimal supersymmetric standard model, assigns pm 1/3 charges to the first and second generations of the quarks, and mp 2 to the first generation of the leptons. As a result, the first two generations of squarks acquire masses of about 7 TeV, and the first generation of the sleptons do those of 40 TeV, respectively, in the presence of one or three pairs of extra vector-like matter {{bf 5},bar{bf 5}}. Non-observation on extra colored particles below 1 TeV at the large hadron collider, and also the flavor violations such as mu^-rightarrow e^-gamma are explained. By virtue of such a gauge symmetry, proton stability can be protected. The other squarks and sleptons as well as the gauginos can obtain masses of order 10^{2-3} GeV through the conventional gravity or gauge mediated SUSY breaking mechanism. The relatively light smuon/sneutrino and the neutralino/chargino could be responsible for the (g-2)_mu deviated from the standard model prediction. The stop mass of sim 500 GeV relieves the fine-tuning problem in the Higgs sector. Two-loop effects by the relatively heavy sfermions can protect the smallness of the stop mass from the radiative correction by the heavy gluino (gtrsim 1 TeV). Extra vector-like matter can enhance the radiative corrections to the Higgs mass up to 126 GeV, and induce the desired mixing among the chiral fermions after U(1)_{B_1+B_2-2L_1} breaking.
We present an economical model where an $S^{}_1$ leptoquark and an anomaly-free $U(1)^{}_X$ gauge symmetry with $X = B^{}_3-2L^{}_mu/3-L^{}_tau/3$ are introduced, to account for the muon anomalous magnetic moment $a^{}_mu equiv (g^{}_mu-2)$ and flavor puzzles including $R^{}_{K^{(ast)_{}}}$ and $R^{}_{D^{(ast)_{}}}$ anomalies together with quark and lepton flavor mixing. The $Z^prime_{}$ gauge boson associated with the $U(1)^{}_X$ symmetry is responsible for the $R^{}_{K^{(ast)_{}}}$ anomaly. Meanwhile, the specific flavor mixing patterns of quarks and leptons can be generated after the spontaneous breakdown of the $U(1)^{}_X$ gauge symmetry via the Froggatt-Nielsen mechanism. The $S^{}_1$ leptoquark which is also charged under the $U(1)^{}_X$ gauge symmetry can simultaneously explain the latest muon $(g-2)$ result and the $R^{}_{D^{(ast)_{}}}$ anomaly. In addition, we also discuss several other experimental constraints on our model.
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